Well, it depends which sound files you want to listen to. I use the Miles Sound System and tools (you don't have to change the extension). To watch the movies, you can use Bink video. Both applications are available here:
http://www.radgametools.com/default.htm)
If you want to manipulate sounds as I did in the recruitable Dustil mod, you'll need to decompress the sounds contained in the streamwaves folder with the Miles sound tools (or similar application.) You don't need to do so if you just want to listen to the files.